org.scijava.parsington.eval

Class AbstractEvaluator

java.lang.Object

org.scijava.parsington.eval.AbstractEvaluator

All Implemented Interfaces:

Evaluator

Direct Known Subclasses:

AbstractStandardEvaluator

public abstract class AbstractEvaluator
extends Object
implements Evaluator

Base class for Evaluator implementations.

Author:

Curtis Rueden

Constructor Summary

Constructors

Constructor and Description
AbstractEvaluator()
AbstractEvaluator(ExpressionParser parser)

Method Summary

Modifier and Type	Method and Description
Object	get(String name) Gets the value of a variable.
ExpressionParser	getParser() Gets the parser used when evaluating expressions.
boolean	isStrict() Gets whether the evaluator is operating in strict mode.
void	set(String name, Object value) Sets the value of a variable.
void	setAll(Map<? extends String,? extends Object> map) Assigns variables en masse.
void	setStrict(boolean strict) Sets whether the evaluator is operating in strict mode.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.scijava.parsington.eval.Evaluator

evaluate, evaluate, evaluate, get, set, value, var

Constructor Detail

AbstractEvaluator

public AbstractEvaluator()

AbstractEvaluator

public AbstractEvaluator(ExpressionParser parser)

Method Detail

getParser

public ExpressionParser getParser()

Description copied from interface: Evaluator

Gets the parser used when evaluating expressions.

Specified by:

getParser in interface Evaluator

Returns:

The expression parser used by this evaluator.

isStrict

public boolean isStrict()

Description copied from interface: Evaluator

Gets whether the evaluator is operating in strict mode.

Specified by:

isStrict in interface Evaluator

Returns:

True iff the evaluator is operating in strict mode.

See Also:

Evaluator.setStrict(boolean)

setStrict

public void setStrict(boolean strict)

Description copied from interface: Evaluator

Sets whether the evaluator is operating in strict mode. Evaluators operate in strict mode by default.

When evaluating strictly, usage of an unassigned variable token in a place where its value is needed will generate an IllegalArgumentException with an "Unknown variable" message; in non-strict mode, such a variable will instead be resolved to an object of type Unresolved with the same name as the original variable.

In cases such as assignment, this may be sufficient to complete the evaluation; for example, the expression foo=bar will complete successfully in non-strict mode, with the variable foo containing an object of type Unresolved and token value "bar". But in cases where the unresolved value is needed as an input for additional operations, the evaluation may still ultimately fail if the operation in question is not defined for unresolved values. For example, the DefaultStackEvaluator will fail with an "Unsupported binary operator" exception when given the expression foo+bar, since foo and bar are unresolved variables, and the + operator cannot handle such objects.

Specified by:

setStrict in interface Evaluator

Parameters:

strict - True iff the evaluator should operate in strict mode.

get

public Object get(String name)

Description copied from interface: Evaluator

Gets the value of a variable.

Specified by:

get in interface Evaluator

Parameters:

name - The name of the variable whose value you want.

Returns:

The variable's value.

set

public void set(String name,
                Object value)

Description copied from interface: Evaluator

Sets the value of a variable.

Specified by:

set in interface Evaluator

Parameters:

name - The name of the variable whose value you want to set.

value - The value to assign to the variable.

setAll

public void setAll(Map<? extends String,? extends Object> map)

Description copied from interface: Evaluator

Assigns variables en masse.

Specified by:

setAll in interface Evaluator

Parameters:

map - A map from variable names to variable values.